Pure oneness comes from being fully committed to the Spirit no matter what. Should you commit to a relationship that has darkness? You commit to go through the darkness to the Light. Helen Schucman and Bill Thetford had a testy relationship. Spirit uses all kinds of assignments. There has to be some sense of attraction, of purpose. In the Course, Jesus says the teaching/learning balance is perfect in lifelong relationship assignments. Spirit uses the body for communication, leading ultimately to communion with the One.